队列研究中多因素调整人群归因危险度的估计及其应用

[目的]介绍多因素调整人群归因危险度(PARp)估计方法及其在队列研究中的应用.[方法]利用2002～2006年建立的上海市男性健康队列(SMHS),在拟合多因素Cox风险比例模型基础上,以男性肺癌为例估计其常见危险因素的PARp.文中分别介绍了PAR在未调整和调整混杂因素情况下的估计方法,以及95％可信区间的计算.数据分析通过SAS程序来实现.[结果]上海市男性健康队列共61 500名对象,截止2010年12月31日,共发生肺癌507例.调整其他因素对肺癌影响后,吸烟、酗酒、慢性支气管炎史、肺癌家族史对肺癌的多因素调整人群归因危险度及其95％可信区间分别为64.31％(54.95％～72.13％)、8.46％ (3.82％ ～12.97％)、6.43％(1.13％～11.56％)、3.43％(1.15 ％～5.62％),其他生活方式因素中水果摄入不足、身体消瘦分别可解释18.33％ (0.93％～34.60％)和3.16％(0.42％～5.84％)的上海市区男性肺癌的发生.[结论]上海市区男性肺癌的发生很大程度上归因于吸烟、酗酒、身体消瘦、水果摄入不足等不良生活方式因素.多因素调整人群归因危险度是一个重要的流行病学指标,尤其对指导病因复杂的慢性疾病预防和控制的公共卫生实践非常重要,值得推广应用.     

Cigarette smoking, alcohol drinking and the risk of gallbladder cancer death: a prospective cohort study in Japan

Gallbladder cancer is a rare cancer with a poor prognosis, and few risk factors have been identified to date. This prospective study was conducted to evaluate the association of cigarette smoking and alcohol consumption with the risk of gallbladder cancer death. A baseline survey in 45 areas throughout Japan was conducted from 1988 to 1990 using a self-administered questionnaire, and a total of 113,496 participants (65,740 women) aged 40-89 years at entry were followed for 15 years. During the follow-up period, 165 gallbladder cancer deaths (95 women) were observed. Among women, the hazard ratio (HR) [95 percent confidence interval: 95% CI] of current smoker was 2.00 [0.91-4.42], when adjusted for age and drinking. There was no clear association between alcohol consumption and the risk. Among men, HR of current smoker was 2.27 [1.05-4.90]. HRs of those who smoked 21 cigarettes or more per day and those with 801-1,000 cigarette-years were 3.18 [1.18-8.53] and 3.44 [1.40-8.45], respectively, and positive linear associations were observed between that risk and the number of cigarettes per day (p for trend = 0.007) or "cigarette-years" (p for trend = 0.012). The alcohol dose was linearly associated with risk (p for trend = 0.004), where the HR among those who consumed 72.0 g or more of alcohol per day was 3.60 [1.29-9.85]. Among both men and women, cigarette smoking may elevate the risk of death from gallbladder cancer. Drinking may pose an elevated risk among men, but that seems to be less true among women.     

Cohort analysis of fruit and vegetable consumption and lung cancer mortality in European men

Our aim was to examine the relationship between fruit and vegetable consumption and lung cancer mortality in a cohort of European males. Around 1970, dietary intake of Finnish, Italian and Dutch middle-aged men was assessed using a cross-check dietary history. Complete baseline information was available for 3,108 men, of whom 1,578 were baseline smokers. We used Cox proportional hazard analyses to calculate risk estimates for the consumption in country-specific tertiles on lung cancer in smokers. During 25 years of follow-up, 149 lung cancer deaths occurred in the smokers. Fruit consumption was inversely associated with lung cancer mortality among smokers; compared with the lowest, adjusted RRs for the intermediate and highest tertiles were 0.56 (0.37-0.84) and 0.69 (0.46-1.02), p-trend 0.05. Only in the Dutch cohort was this association statistically significant [adjusted relative risks (RRs) 1.00, 0.33 (0.16-0.70) and 0.35 (0.16-0.74), p-trend 0.004]. In Finland lung cancer risk was lower with higher fruit intake but not significantly, whereas in Italy no association was observed. Stratifying on cigarette smoking intensity (non, light and heavy) revealed an inverse association in the heavy smokers only [adjusted RRs (95% confidence intervals [CI]) 1; 0.47 (0.26-0.84); 0.40 (0.20-0.78)). Vegetable consumption was not related to lung cancer risk in smokers. However, analyses stratified on cigarette smoking intensity gave some indication for a lower lung cancer risk with higher intake. In conclusion, in this prospective analysis among European smoking men, fruit intake was inversely related to lung cancer mortality. This association was confined to heavy cigarette smokers.     

Cigarette smoking and subsequent risk of lung cancer by histologic type in middle-aged Japanese men and women: the JPHC study

In order to update the findings of relative risk associated with cigarette smoking for lung cancer by histologic type in Japan, the data from a population-based cohort study of 91,738 men and women were analyzed. During 1990-1999, 422 lung cancer incident cases were identified. The relative risk for all incident cases associated with current smokers versus non-smokers was 4.5 [95% confidence interval (CI): 3.0-6.8] and 4.2 (95% CI: 2.4-7.2), for men and women, respectively. When divided by histologic type, relative risk for squamous cell carcinoma and small cell carcinoma was 12.7 (95% CI: 4.7-34.7) and 17.5 (95% CI: 4.9-62.1), while for adenocarcinoma it was 2.8 (95% CI: 1.6-4.9) and 2.0 (95% CI: 0.8-5.0) for men and women, respectively. We confirmed that the lung cancer risk in men rose with increasing cigarette smoking, especially the duration of smoking among current smokers and decreased after the cessation of smoking among former smokers. Unlike the US or European countries, the relative risk did not increase in this updated study, compared with previous studies in 1960s to 1990s in Japan either for all incident cases or for specific histologic types and the magnitude of relative risks was substantially lower than that observed in the US or European countries, especially for adenocarcinoma.     

A prospective cohort study of cigarette smoking and pancreatic cancer in Japan

Objective: To examine the association of cigarette smoking with the risk of death from pancreatic cancer in a prospective cohort study. Methods: A total of 110,792 inhabitants, aged 40–79 years (46,465 men and 64,327 women), were enrolled from 1988 to 1990 and followed up for mortality to the end of 1997. At baseline a self-administered questionnaire was used to obtain information on cigarette smoking and other lifestyle factors. Results: During the follow-up period (mean ± SD: 8.1 ± 1.8 years), 225 deaths due to pancreatic cancer were identified. After adjustment for age, body mass index, history of diabetes mellitus, and gallbladder diseases, the relative risks (RRs) for current smokers were 1.6 (95% CI 0.95–2.6) in males, and 1.7 (95% CI: 0.84–3.3) in females. Men who smoked more than 40 cigarettes per day had a substantially higher risk of pancreatic cancer, with a RR of 3.3 (95% CI: 1.4–8.1). A significantly decreasing trend in risk with increasing years after smoking cessation was observed (trend p = 0.04) among male ex-smokers. The RRs were 0.85 (95% CI 0.36–2.0) and 0.85 (0.36–2.0) for those who had quit smoking for 10–19 and 20 years, respectively. Conclusions: Our cohort study confirmed that cigarette smoking was associated with an increased risk of death from pancreatic cancer.     

Tuberculosis,smoking and risk for lung cancer incidence and mortality

Among the exposures associated with risk for lung cancer, a history of tuberculosis (TB) is one potentially important factor, given the high prevalence of TB worldwide. A prospective cohort study was conducted to evaluate the associations of preexisting pulmonary TB with lung cancer incidence and mortality. The cohort consisted of 1,607,710 Korean adults covered by the National Health Insurance System who had a biennial national medical examination during 1997–2000. During up to 16 years of follow‐up, there were 12,819 incident cases of lung cancer and 9,562 lung cancer deaths. Using Cox proportional hazards models and controlling for age, cigarette smoking and other covariates, the presence of underlying TB was significantly associated with increased risk for lung cancer incidence (HR 1.37 in men with 95% CI 1.29–1.45; HR 1.49 in women with 95% CI 1.28–1.74) and mortality (HR 1.43 in men with 95% CI 1.34–1.52; HR 1.53 in women with 95% CI 1.28–1.83). We also observed a dose‐response relationship between number of cigarettes smoked daily and lung cancer risk. There was no evidence for synergism between a history of TB and smoking. The elevation in risk is relatively modest, particularly in comparison to that from smoking, and a prior history of TB is not likely to be useful risk indicator for clinical purposes. In populations with high prevalence of TB, it can be considered for incorporation into models for lung cancer risk prediction.     

Smoking cessation and lung cancer risk in an Asian population: Findings from the Singapore Chinese Health Study

Background:

Smoking cessation is an important strategy for reducing the harmful effects of tobacco, particularly in the prevention of lung cancer; however, prospective data on the impact of smoking cessation on lung cancer risk in Asian populations are limited.

Methods:

We studied a population-based cohort of Chinese men and women aged 45–74 years – participants of the Singapore Chinese Health Study. Information on smoking, lifestyle and dietary habits was collected at the time of recruitment in 1993–1998; and smoking status was assessed again at a second interview in 1999–2004 (mean interval 5.8 years). Participants were followed up to 31 December 2007, and incident cases of lung cancer were ascertained by linkage with population-wide registries.

Results:

Among 45 900 participants, there were 463 incident cases of lung cancer. Relative to current smokers, those who quit smoking subsequent to baseline assessment had a 28% decrease in the risk of lung cancer (adjusted hazard ratio (HR) 0.72; 95% CI (95% confidence interval): 0.53–0.98). The risk was less than half in ex-smokers who had quit before the first interview and maintained their status (HR 0.42; 95% CI: 0.32–0.56).

Conclusions:

Reduction in lung cancer incidence with smoking cessation in Asian populations is substantial and can be observed within a few years after quitting.     

Vegetable and fruit consumption and lung cancer risk in the Netherlands Cohort Study on Diet and Cancer

Objective: The purpose was to study the association between vegetable and fruit consumption and lung cancer incidence using 1074 cases after 6.3 years of follow-up in the Netherlands Cohort Study. Methods: Dietary intake was assessed using a 150-item food-frequency questionnaire. Multivariate models were used including age, sex, family history of lung cancer, highest educational level attained, and smoking history. Results: Statistically significant inverse associations were found with total vegetables and most vegetable groups. Rate ratios (RRs) based on consumption frequency showed the strongest effect of vegetables from the Brassica group (RR 0.5, 95% confidence interval (95% CI) 0.3–0.9, for consumption 3 times per week versus once a month). RR of highest versus lowest quintile of total vegetable consumption was 0.7 (95% CI 0.5–1.0, p-trend 0.001). Statistically significant inverse associations were found for all fruits listed in the questionnaire. RRs for quintiles of total fruit intake were 1.0, 0.7, 0.6, 0.6 and 0.8 respectively (p-trend < 0.0001). Protective effects of fruits and vegetables were stronger in current than in former smokers, and weaker for adenocarcinomas than for other types of tumors. Conclusions: Inverse associations with lung cancer are found for both vegetable and fruit intake, but no specific type of vegetable or fruit seems to be particularly responsible.     

Intake of Common Alcoholic and Non-Alcoholic Beverages and Breast Cancer Risk among Japanese Women: Findings from the Japan Collaborative Cohort Study

This study investigated the association between intake of common alcoholic and non-alcoholic beverages and breast cancer risk among Japanese women. This study included 33,396 Japanese women aged 40–79 years from 24 areas in Japan from the Collaborative Cohort study. During the follow-up period (≥20 years), 245 incidents or mortal breast cancers were documented. Multivariable logistic regression analysis was performed to assess the independent association between breast cancer risk and the intake of Japanese green tea, coffee, and alcohol. Japanese green tea was the most commonly consumed non-alcoholic beverage (81.6% of participants), followed by coffee (34.7%) and alcohol (23.6%). No significant associations were identified between the intake of green tea and coffee with breast cancer risk (odds ratio OR 1.15, 95% confidence interval [CI] 0.82–1.60, and OR 0.84, 95% CI 0.64–1.10, respectively). Alcohol intake was associated with significant breast cancer risk (OR 1.46, 95% CI 1.11–1.92), and even infrequent alcohol consumption (     

Interaction between tobacco smoking and hepatitis B virus infection on the risk of liver cancer in a Chinese population

Although tobacco smoking has been reported as a risk factor for liver cancer, few studies have specifically explored the association among Chinese females and the potential interaction between smoking and other risk factors. A population‐based case–control study was conducted and 2,011 liver cancer cases and 7,933 healthy controls were enrolled in Jiangsu, China from 2003 to 2010. Epidemiological data were collected, and serum hepatitis B surface antigen (HBsAg) and anti‐HCV antibody were measured. Unconditional logistic regression was used to examine association and potential interaction, while semi‐Bayes (SB) method was employed to make estimates more conservative. The prevalence of serum HBsAg positivity was 43.2% among cases and 6.5% among controls. The adjusted odds ratios (OR) for ever smoking were 1.62 (95% confidence interval [CI]: 1.33–1.96) among male and 0.82 (95% CI: 0.53–1.26) among female. Age at first cigarette, duration of smoking and pack‐years of smoking were all significantly associated with liver cancer among men. Compared to HBsAg‐negative never smokers, the adjusted ORs were 1.25 (95% CI: 1.03–1.52) for HBsAg‐negative ever smokers, 7.66 (95% CI: 6.05–9.71) for HBsAg‐positive never smokers, and 15.68 (95% CI: 12.06–20.39) for HBsAg‐positive ever smokers. These different odds ratios indicated super‐additive (RERI: 7.77, 95% CI: 3.81–11.73) and super‐multiplicative interactions (ROR: 1.64, 95% CI: 1.17–2.30) between hepatitis B virus (HBV) infection and tobacco smoking. Most associations and interactions detected remained statistically significant after SB adjustments. Tobacco smoking and HBV infection positively interact in the development of liver cancer.     

Long‐term exposure to fine particulate matter air pollution and the risk of lung cancer among participants of the Canadian National Breast Screening Study

Recently, air pollution has been classified as a carcinogen largely on the evidence of epidemiological studies of lung cancer. However, there have been few prospective studies that have evaluated associations between fine particulate matter (PM_2.5) and cancer at lower concentrations. We conducted a prospective analysis of 89,234 women enrolled in the Canadian National Breast Screening Study between 1980 and 1985, and for whom residential measures of PM_2.5 could be assigned. The cohort was linked to the Canadian Cancer Registry to identify incident lung cancers through 2004. Surface PM_2.5 concentrations were estimated using satellite data. Cox proportional hazards models were used to characterize associations between PM_2.5 and lung cancer. Hazard ratios (HRs) and 95% confidence intervals (CIs) computed from these models were adjusted for several individual‐level characteristics, including smoking. The cohort was composed predominantly of Canadian‐born (82%), married (80%) women with a median PM_2.5 exposure of 9.1 µg/m³. In total, 932 participants developed lung cancer. In fully adjusted models, a 10 µg/m³ increase in PM_2.5 was associated with an elevated risk of lung cancer (HR: 1.34; 95% CI = 1.10, 1.65). The strongest associations were observed with small cell carcinoma (HR: 1.53; 95% CI = 0.93, 2.53) and adenocarcinoma (HR: 1.44; 95% CI = 1.06, 1.97). Stratified analyses suggested increased PM_2.5 risks were limited to those who smoked cigarettes. Our findings are consistent with previous epidemiological investigations of long‐term exposure to PM_2.5 and lung cancer. Importantly, they suggest associations persist at lower concentrations such as those currently found in Canadian cities.     

Body mass index and mortality from lung cancer in smokers and nonsmokers: A nationally representative prospective study of 220,000 men in China

Low body mass index (BMI) has been associated with increased risk of lung cancer. However, the nature of the association, especially in populations with relatively low BMI, is less well characterized, as is the relevance to it of smoking. A nationally representative prospective cohort study included 217,180 Chinese men aged 40–79 years in 1990–91 who had no prior history of cancer and were followed up for 15 years. Standardized hazard ratios (HRs) were calculated for lung cancer mortality by baseline BMI. The mean baseline BMI was 21.7 kg/m², and 2,145 lung cancer deaths were recorded during 15 years of follow‐up. The prevalence of smoking was strongly inversely associated with BMI, but no apparent relationship was seen between amount smoked (or other measures of smoking intensity) and BMI among smokers. Overall there was a strong inverse association between BMI and lung cancer mortality (p < 0.0001 for trend) after excluding the first 3 years of follow‐up. This association appeared to be confined mainly to current smokers, with no apparent relationship in nonsmokers (p < 0.001 for difference between slopes). Among current smokers, the inverse association appeared to be log‐linear, with each 5 kg/m² lower BMI associated with a 35% (95% confidence interval: 24–46%; p < 0.0001) higher lung cancer mortality, and it persisted after excluding those who had reported poor health status or history of any disease or respiratory symptoms at baseline. In this relatively lean Chinese male population, low BMI was strongly associated with increased risk of lung cancer only among current smokers. © 2009 UICC     

The cumulative risk of lung cancer among current, ex- and never-smokers in European men

Recent analyses based on UK data indicate that people who stop smoking, even well into middle age, avoid most of their subsequent risk of lung cancer. We investigated whether similar absolute risks of lung cancer in men are found in other European countries with different smoking patterns and at different stages of their lung cancer epidemic. Using data for men from a multicentre case-control study of lung cancer in the UK, Germany, Italy and Sweden, and including 6523 lung cancer cases and 9468 controls, we combined odds ratio estimates with estimates of national lung cancer incidence rates to calculate the cumulative risk of lung cancer among men by age 75. Lung cancer cumulative risks by age 75 among continuing smokers were similar for the UK, Germany and Italy at 15.7, 14.3 and 13.8% respectively, whereas the cumulative risk among Swedish male smokers was 6.6%. The proportion of the risk of lung cancer avoided by quitting smoking before the age of 40 was comparable between the four countries, at 80% in Italy and 91% in the UK, Germany and Sweden. Similarly, the proportion of the excess risk avoided by quitting before the age of 50 ranged from 57% in Italy to 69% in Germany. Our results support the important conclusion that for long-term smokers, giving up smoking in middle age avoids most of the subsequent risk of lung cancer, and that lung cancer mortality in European men over the next three decades will be determined by the extent to which current smokers can successfully quit smoking.     

Neutrophil-to-lymphocyte ratio and risk of lung cancer mortality in a low-risk population: A cohort study

Neutrophil-to-lymphocyte ratio (NLR) is associated with poor prognosis in patients with lung cancer, but the predictive role of NLR on the risk of developing lung cancer is unknown. We investigated the association between NLR and lung cancer mortality in lung cancer-free adults. A cohort study was performed with 527,124 Korean adults who were free of lung cancer and were followed for up to 16 years. Vital status and lung cancer-related deaths were ascertained through national death records. Hazard ratios (HRs) and 95% confidence intervals (CIs) for lung cancer mortality were estimated using a Cox proportional hazards model. During 4,567,495.8 person-years of follow-up, 574 lung cancer deaths were identified. A higher NLR was positively associated with lung cancer mortality. The multivariable-adjusted HR (95% CI) for lung cancer mortality comparing quintiles 2, 3, 4 and 5 of NLR to the lowest quintile were 1.26 (0.96–1.67), 1.23 (0.93–1.63), 1.33 (1.01–1.75) and 1.47 (1.13–1.92), respectively. The highest risk of lung cancer mortality was also observed in the highest NLR quintile among never-smokers and low-risk individuals after adjusting for lung function and other possible confounders. Platelet-to-lymphocyte ratio showed an inverse J-shaped association with lung cancer mortality in men but the trends in women, low-risk individuals or never-smokers were neither linear nor U-shaped. In this large cohort of young and middle-aged individuals, NLR was independently associated with increased risk of lung cancer mortality in low-risk individuals, indicating a role of systemic inflammation in lung cancer mortality in our study population.     

Pulmonary tuberculosis increases the risk of lung cancer: a population-based cohort study

BACKGROUND:

The possible effect of pulmonary tuberculosis (TB) on subsequent lung cancer development has been suspected, but the evidence remains inconsistent. The purpose of this study was to perform a nationwide population‐based cohort study to investigate the risk of lung cancer after pulmonary TB infection.

METHODS:

This nationwide population‐based cohort study was based on data obtained from the Taiwan National Health Insurance Database. In total, 5657 TB patients and 23,984 controls matched for age and sex were recruited for the study from 1997 to 2008.

RESULTS:

The incidence rate of lung cancer (269 of 100,000 person‐years) was significantly higher in the pulmonary TB patients than that in controls (153 of 100,000 person‐years) (incidence rate ratio [IRR], 1.76; 95% confidence interval [CI], 1.33‐2.32; P < .001). Compared with the controls, the IRRs of lung cancer in the TB cohort were 1.98 at 2 to 4 years, 1.42 at 5 to 7 years, and 1.59 at 8 to 12 years after TB infections. The multivariate Cox proportional hazards model revealed pulmonary TB infections (hazard ratio [HR], 1.64; 95% CI, 1.24‐2.15; P < .001) and chronic obstructive pulmonary disease (HR, 1.09; 95% CI, 1.03‐1.14; P = .002) to be independent risk factors for lung cancer.

CONCLUSIONS:

Pulmonary infection with TB is associated with an increased risk of lung cancer. Cancer 2011. © 2010 American Cancer Society.     

Mortality Attributable to Second Hand Smoking in Morocco: 2012 Results of a National Prevalence Based Study

Purpose: To estimate the number of deaths attributable to second hand smoking (SHS) in Morocco in 2012. Materials and Methods: prevalence based study focusing on mortality from ischaemic heart disease (IHD) and lung cancer among non-smokers aged 35 and over. Prevalence of SHS among never smokers was gathered from a national cross sectional survey on tobacco and population attributable risk (PAR) was calculated by applying PARs to mortality. The analyses were stratified by sex, age and area of exposure. Results: Rates for exposure to SHS among men aged 35-64 years ranged from 20.0% at home to 57.4% at work. Among non-smoking Moroccans aged 35 and over, 233 (IC: 147 - 246) deaths were attributable to exposure to SHS; 156 (IC: 100 - 221) in women and 77 (IC: 44 -125) in men. A total of 173 (122 - 222) deaths were estimated to have been caused by exposure only at home, 34 (9 - 76) by exposure only at the work place and 26 (15 - 58) by exposure both at home and work places. Exposure to SHS could be responsible for 182 (128 - 237) deaths from IHD and 51 (19 - 109) from lung cancer. Conclusions: These data confirm that SHS needs urgent attention in Morocco.     

Risk Factors for Multiple Myeloma: Evidence from the Japan Collaborative Cohort (JACC) Study

This study assessed the association of multiple myeloma (MM) with age, body mass index (BMI, kg/m2), physicalactivity, occupational history, and medical history for a Japanese cohort of 46,157 men and 63,541 women aged 40-79 years followed during 1988-2003 years. Cox proportional hazard model was mainly used to estimate the age andsex adjusted hazard ratio (HR) of MM including 95% confidence interval (CI) for both sexes. Same model, adjustedfor age, was also used for each sex. In total, 98 MM deaths (men=49 and women=49) was observed for both sexes.Higher age groups (60-69 and 70-79 years) experienced significantly higher unadjusted HR of MM than the agegroup of 40-49 years. Men revealed significantly higher age-adjusted MM than women (HR=1.5; 95% CI=1.0-2.2).For both sexes, higher BMI of ≥30 kg/m2 (HR=2.8; 95% CI=1.0-7.7), walking ≤30 minutes/day (HR=2.0; 95% CI=1.2-3.4), worried about personal relationship in working place (HR=2.3; 95% CI=1.3-4.2), restricted own pace in workingplace (HR=1.9; 95% CI=1.0-3.4), and history of peptic ulcer (HR=1.7; 95% CI=1.0-2.7) significantly increased ageand sex adjusted MM risk. Some of the above-mentioned significant associations became insignificant for age adjustedsex specific analyses. However, these findings should be validated by further epidemiologic studies in Japan beforegeneralization.     

Cigarette smoking and lung cancer--relative risk estimates for the major histological types from a pooled analysis of case-control studies

Lung cancer is mainly caused by smoking, but the quantitative relations between smoking and histologic subtypes of lung cancer remain inconclusive. By using one of the largest lung cancer datasets ever assembled, we explored the impact of smoking on risks of the major cell types of lung cancer. This pooled analysis included 13,169 cases and 16,010 controls from Europe and Canada. Studies with population controls comprised 66.5% of the subjects. Adenocarcinoma (AdCa) was the most prevalent subtype in never smokers and in women. Squamous cell carcinoma (SqCC) predominated in male smokers. Age-adjusted odds ratios (ORs) were estimated with logistic regression. ORs were elevated for all metrics of exposure to cigarette smoke and were higher for SqCC and small cell lung cancer (SCLC) than for AdCa. Current male smokers with an average daily dose of >30 cigarettes had ORs of 103.5 (95% confidence interval (CI): 74.8-143.2) for SqCC, 111.3 (95% CI: 69.8-177.5) for SCLC and 21.9 (95% CI: 16.6-29.0) for AdCa. In women, the corresponding ORs were 62.7 (95% CI: 31.5-124.6), 108.6 (95% CI: 50.7-232.8) and 16.8 (95% CI: 9.2-30.6), respectively. Although ORs started to decline soon after quitting, they did not fully return to the baseline risk of never smokers even 35 years after cessation. The major result that smoking exerted a steeper risk gradient on SqCC and SCLC than on AdCa is in line with previous population data and biological understanding of lung cancer development.     

Population attributable risks of cigarette smoking for deaths of all causes,all cancers and other chronic diseases among adults aged 40-74 years in urban Shanghai,China

Objective

To evaluate the population attributable risks (PARs) between cigarette smoking and deaths of all causes, all cancers, lung cancer and other chronic diseases in urban Shanghai.

Methods

In total, 61,480 men aged 40-74 years from 2002 to 2006 and 74,941 women aged 40-70 years from 1997 to 2000 were recruited to undergo baseline surveys in urban Shanghai, with response rates of 74.0% and 92.3%, respectively. A Cox proportional hazards regression model was used to estimate relative risks (RRs) and 95% confidence intervals (95% CIs) of deaths associated with cigarette smoking. PARs and 95% CIs for deaths were estimated from smoking exposure rates and the estimated RRs.

Results

Cigarette smoking was responsible for 23.9% (95% CI: 19.4-28.3%) and 2.4% (95% CI: 1.6-3.2%) of all deaths in men and women, respectively, in our study population. Respiratory disease had the highest PAR in men [37.5% (95% CI: 21.5-51.6%)], followed by cancer [31.3% (95% CI: 24.6-37.7%)] and cardiovascular disease (CVD) [24.1% (95% CI: 16.7-31.2%)]. While the top three PARs were 12.7% (95% CI: 6.1-19.3%), 4.0% (95% CI: 2.4-5.6%), and 1.1% (95% CI: 0.0-2.3%), for respiratory disease, CVD, and cancer, respectively in women. For deaths of lung cancer, the PAR of smoking was 68.4% (95% CI: 58.2-76.5%) in men.

Conclusions

In urban Shanghai, 23.9% and 2.4% of all deaths in men and women could have been prevented if no people had smoked in the area. Effective control programs against cigarette smoking should be strongly advocated to reduce the increasing smoking-related death burden.     

Cigarette smoking and the risk of gastric cancer: a pooled analysis of two prospective studies in Japan

To examine the association between cigarette smoking and the risk of gastric cancer, we conducted a pooled analysis of 2 population-based prospective cohort studies in rural northern Japan. Cohort 1 included 9,980 men (>or=40 years old) and Cohort 2 included 19,412 men (40-64 years old). The subjects completed a self-administered questionnaire on cigarette smoking and other health habits. We identified 228 cases of gastric cancer among Cohort 1 subjects (9 years of follow-up with 74,073 person-years) and 223 among Cohort 2 subjects (7 years of follow-up with 141,675 person-years). From each cohort, we computed the relative risk (RR) and 95% confidence interval (CI) of gastric cancer associated with smoking using a Cox regression analysis and pooled these estimates to obtain summary measures. The pooled multivariate RRs (95% CIs) for current smokers and past smokers compared to subjects who had never smoked were 1.84 (1.39-2.43) and 1.77 (1.29-2.43), respectively. The higher number of cigarettes smoked per day among current smokers was associated with a linear increase in risk (trend p < 0.05). The significant increase in risk for past smokers remained for up to 14 years after cessation. An increased risk was noted for cancer of the antrum but not for cardia or body lesions. The risk was increased for both differentiated and nondifferentiated histologic subtypes. Our findings support the hypothesis that cigarette smoking is a risk factor for gastric cancer.